Recently, there has been a need for a rocket propellant charge or a gas generating charge used for launching rockets, especially for launching small size missiles.
The rocket propellant charge needs to burn up in a short time and produce a relatively large thrust, and the gas generating charge also needs to burn up in a short time and generate a relative large amount of gas.
They are both used for launching rockets. The former is used in rocket motors of boosters and the latter is used in gas generator devices of launchers.
Charges in such rocket motors are of a short duration burn-up type and gas generator devices have been hitherto applied in the below stated manners.
The propellants are most generally used in single perforation or multiperforation form and they have been applied to multigrain systems for rocket motors in which tubular single or multiperforated propellants are charged in a rocket motor in a large number.
There has been known in a special case of a gun propellant charge a method for preparing a charge which comprises cutting a propellant in the form of sheets of a predetermined size, piling the resultant sheets and fixing them by threads.
However, these have respective particular drawbacks when they are applied in the rocket motors or the gas generator devices which generate pressures of 20 to 200 kg/cm.sup.2 during the short burn-up time.
The single perforated or multiperforated propellant can not obtain a uniform pattern of burning surface area owing to the shape of the powder charge and the non-uniformity is remarkable in the pressure-time and/or thrust-time relation characteristics. Further, these propellants have defects in that when they are used for a rocket motor, they burn up into small grains, with the result that burning grains scatter on all sides and the burning efficiency thereby decreases.
Concerning single perforated propellants of the multigrain system, when they are used for a rocket motor, it is difficult to maintain them and consequently it is difficult to prevent some broken pieces of burning propellant from scattering out of a motor.
In addition, the above stated process comprising piling the sheets of propellant and fixing them by threads or the like is useful for a gun propellant in which such sheets are used under a pressure above 500 kg/cm.sup.2 but is not useful for a rocket motor or a gas generating device in which it is used at a pressure in a range of 20-200 kg/cm.sup.2, because a uniform combustion can not be obtained in this pressure range.